Good to hear new ideas,
Part of the problem of loading from the default sprite table is, What if somebody has completely removed it.

Options to edit the pointers NSE is using ( Sprite Tables, Palette Tables, ect) could, and might be added soon
-Expect to see in 1.7 possibly

Maybe you could use the table in settings.ini for that, or prompt for table on opening (while still having as choice later), or just saying "Load a table." on the blank sprite, directing people to the option. Any of those could work.